The US Department of Homeland Security has warned California, New York and Illinois, which serve as "sanctuary states" for illegal immigrants, against not cooperating with the US Immigration and Customs Enforcement (ICE), amid the Trump administration's effort to deport millions who entered the US illegally. Among other things, Illinois and New York refused to share information with ICE regarding illegal residents imprisoned for crimes other than illegal entry into the US, while California did not respond to this request at all.